1. Field of the Invention
The invention relates to an improved process for preparing cinacalcet hydrochloride.
2. Related Art
Cinacalcet hydrochloride is a commercially marketed pharmaceutically active substance known to be useful for the treatment of hyperparathyroidism and the preservation of bone density in patients with kidney failure or hypercalcemia due to cancer. Cinacalcet hydrochloride is the generic international denomination for N-[1-(R)-(−)-(1-naphthyl)ethyl]-3-[3-(trifluoromethyl)phenyl]-1-aminopropane hydrochloride, which has the Formula (I) given below:

Cinacalcet hydrochloride is an oral calcimimetic drug. In the United States, it is marketed under the name Sensipar® and, in Europe, it is marketed under the name Mimpara® and Parareg®. It has been approved for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease on dialysis and for the treatment of hypercalcemia in patients with parathyroid carcinoma.
U.S. Pat. No. 6,011,068 generally describes cinacalcet and its pharmaceutically acceptable acid additions salts but does not provide any examples for the preparation of the same.
U.S. Pat. No. 6,211,244 describes cinacalcet and its pharmaceutically acceptable acid chloride addition salt but does not provide any examples for the preparation of cinacalcet and/or cinacalcet hydrochloride.
U.S. Pat. No. 7,247,751 discloses that the crystalline cinacalcet hydrochloride currently marketed as Sensipar® is characterized as crystalline Form I (denominated as Form I), and encompasses processes for its preparation. The examples provided, however, are not efficient for industrial implementation, i.e., do not specify the purity of the obtained cinacalcet hydrochloride, and use large volumes of acidifying agent and solvents.
International Patent Publication No. WO 2008/058236 provides additional processes for making cinacalcet hydrochloride. Among others, Example 26 of International Patent Publication No. WO 2008/058236 describes the preparation of cinacalcet hydrochloride via treating cinacalcet acetate salt with hydrochloric acid.
There is therefore a need of providing an efficient and economic process for preparing cinacalcet hydrochloride be suitable for industrial implementation.